The present invention relates broadly to agricultural leveling implements for eliminating surface irregularities. More specifically, the present invention relates to a land plane that is foldable between a narrow, transport position and a wider, deployed position.
As will be appreciated by those skilled in the agricultural arts, it is generally desirable to provide a level field free of obstructions and major surface irregularities. Such irregularities may result, for example, from tilling, aeration, and harvesting procedures as well as from natural causes such as extreme winds or rains. If a field is not properly leveled for cultivation, crops may suffer from a variety of causes. Crops may be seriously affected by surface irregularities resulting in standing water, flooding, leeching, excessive runoff, or the like. It is particularly critical that the land be leveled to control water flow through and upon a cultivated area. For example, strict control of water flow is critical for the proper irrigation and flooding of rice. If the field is marked with surface irregularities at the outset, the rice farmer will have difficulty defining proper flood levees. Hence, it is desired to provide an implement for leveling a field surface to be cultivated.
In the prior art, various land planes have been proposed. However, there are various disadvantages associated with known prior art land planes. Importantly, the prior art planes are restricted in width, because any agricultural implement cannot exceed the sixteen to eighteen foot width required to traverse rural roads or highways. Hence the width of prior art land planes is generally limited to sixteen or eighteen feet. To achieve a satisfactory leveling, the farmer must pass the narrow leveling blade over the field numerous times and in various directions to achieve a fully level surface. This procedure involves substantial effort and expense.
Moreover, because of their limited size, known prior art planes do not provide sufficient drag to properly level hardened surfaces. Hence, it is desired to provide a land plane which covers a substantially larger area in a single pass, but which may be conveniently and legally towed over adjacent access roads. Moreover, it is desired to provide a plane that avoids creation of irregularities such as tire ruts and the like.
The use of foldable wings to define a broader tool carriage is well known in the art. A wide variety of foldable implement carriages have been proposed which can be collapsed for convenient transport on public roads. However, none of the prior art implements known to me satisfactorily addresses the need for a conveniently foldable, broad-based land plane.
Multi-section earth working implements comprising a foldable tractor-driven framework are disclosed in U.S. Pat. Nos. 3,529,674 issued Sep. 22, 1970 to Todd; No. 3,640,345 issued to Sosalla on Feb. 8, 1972; and No. 3,944,001 issued to Warner on Mar. 16, 1976. Ankenman teaches a foldable implement comprising a pair of trailing wings for controlling oscillation in U.S. Pat. No. 3,990,521 issued Nov. 9, 1976.
A tillage implement comprising a pair of folding, offset beams is disclosed by Anderson U.S. Pat. No. 4,327,932 issued May 4, 1982. A foldable offset seed drill is disclosed in U.S. Pat. No. 4,660,651 issued Apr. 28, 1987 to Fenninger. Frager U.S. Pat. No. 3,830,313 issued Aug. 20, 1974 and Poland U.S. Pat. No. 3,828,860 issued Aug. 13, 1974 both disclose folding implement frames for transporting a plurality of disk harrow arms. The arms project radially from the foldable frame in at least four directions. The purpose of the latter-described arrangement is to compete turning of the soil in various directions.
While folding agricultural devices are disclosed in the prior art, none known to me teaches a foldable land plane that is capable of correcting surface irregularities across a large sector of the field in a single pass. Moreover, none provides structure that adequately prepares a wide land surface for irrigation levees.